CT-guided Ablation of the Ganglion Impar for Pelvic Tumors: Comparethe Addition of Ketorolac or Dexamethasone

The aim of this study is to compare the effect of administration of ketorolac versus dexamethasone on CT guided ganglion impar block with ethyl alcohol in patients with pelvic tumor.

The primary outcome will be the onset of sensory block, patient satisfaction measured by patient satisfaction score ( Jones KD, Sutton C., 2003), intensity of pain measured by a linear visual analogue scale (VAS) (Bourdel, N. et al., 2014) and incidence of early complications and side effects.

The secondary outcome will include the duration of sensory block, the time and the amount of post-procedure analgesic requirement, itching and any associated complications.

We hypothesized that CT guided ganglion impar block will be a good choice in pain reduction in patients with chronic pelvic pain. Pain reduction will be greater in dexamethasone and ketorolac group compared to alcohol group.Preinterventional assessment includes general, pain specific history taking (location, quality, intensity, relieving and provoking incidences) and pain in specific physical examination (inspection and palpation) will be carried out. Type of pelvic tumor, investigation related to tumor, previous operations, chemotherapy, basic demographic variables including age, sex and body mass index will be recorded. Routine investigations include bleeding profiles (bleeding time, clotting time, INR), blood picture, liver and kidney function tests will be carried out. A linear visual analogue scale (VAS) on a scale of 0-10 mm (where 0 for no pain and 10 for worst pain) will be explained to each patient. Written informed consent will be obtained, detailed information on risks and complications will be provided.The vital signs (heart rate, blood pressure, spo2) will be recorded. After establishing an access to peripheral venous line, 500 ml normal saline will be given to the patient, the patient will be in the prone position with a pillow under the abdomen to allow flexion of the lumbo-sacral spine with internal rotation of the lower extremities.All patients will be asked to empty the bladder and rectum before the start of the procedure to facilitate needle placement and avoid inadvertent injection. The pre-injection planning images will be obtained using CT with 2 mm axial section thickness. A needle localizer will be placed on the skin surface to identify and mark the sacro-coccygeal disc.

Sterilization of The patient's sacral and gluteal areas will be provided with povidone iodine antiseptic solution and this area was circumferentially draped with sterile towels. Under aseptic technique, a skin wheal will be raised with 2 ml lignocaine 0.5% using 23 G needle either in midline or paramedian approach. After identifying the ganglion impar, usually at the level of the sacro-coccygeal disc, a 25 G, 9 cm long spinal needle will be introduced at approximately 6-9 cm from midline and a small amount of non-ionic contrast medium (0.5 ml iopamidol; 300 mg/ml) will be injected. The midline approach may be selected according to patient position and operative condition. In the midline approach the sacro-coccygeal disc is identified and needle will be introduced perpendicular through the disc and just encroaching upon presacro-coccygeal space. The patient will be rescanned to confirm the position of the tip of the spinal needle at the anterior aspect of the sacro-coccygeal junction in the retroperitoneal space (Datir A and Connell D., 2010).

Thereafter, 3 ml lidocaine 2% will be injected, three minutes later 5 ml absolute alcohol 95% ± 8 mg dexamethasone or (15 mg ketorolac) will be slowly injected for therapeutic chemical neurolysis.